1. Field of the Invention
The invention relates to optical components, and particularly to a variable optical attenuator with a photoelectric detector.
2. Description of the Related Art
Telecommunication and data transfers over networks are increasingly being implemented using optical components. To enable the power of an optical beam to be reduced in a controlled manner, various types of variable optical attenuators (VOA) have been developed. Amongst these, a micro-electro-mechanical system (MEMS)-type attenuator is commonly-used. The MEMS optical attenuator comprises a pair of collimators and a MEMS driving shade. Since mode field diameters vary depending on the wavelength, this kind of MEMS optical attenuator may have large wavelength-dependent losses.
FIG. 1 illustrates another type of MEMS optical attenuator, comprising an optical fiber holder 101 which holds optical fibers 1011 and 1012, a lens 103 and a mirror 104. As the mirror 104 rotates, the light entering the optical fiber 1012 is changed.
However, the above-mentioned MEMS optical attenuators are not capable of detecting their own attenuation performance, and therefore their reliability cannot be guaranteed.